Spark plug



July 3l, 1934. G. SHELL Er AL SPARK PLUG Filed NOV. 16. 1932 Squeak-WHATTORNEY.

latented July al., luar SPARK PLUG Gustave A. sneu, Garden city, andBernard Zettel-land, Detroit, Mich.

` Application November 16, 1932, Serial No. 642,910

2 Claims.

Our invention relates to new and useful improvement in a spark plug andhas for its object the provision of a spark plug which may beeconomically manufactured, which may be easily and quickly assembled ata minimum cost and which will be durable and efficient in use.

Another object of the invention is the provision of a spark plugpossessed of a maximum eniciency and formed from a minimum number ofparts.

Another object of the invention is the provision of a spark plug havingan insulating core provided with a coiled electrode threaded therein andprojecting outwardly therefrom its opposite ends thereof.

Gther objects will appear hereinafter.

The invention consists in the combination and arrangement of partshereinafter described and claimed.

The invention will be best understood by a reference to the accompanyingdrawing which forms a part of this speciiication, and in which,

Fig. 1 is a longitudinal central sectional view of the invention.

Fig. 2 is a sectional view taken on line 2-2 of Figure 1.

Fig. 3 is a sectional view taken on line 3 3 of F18. 1.

Fig. 4 is a longitudinal central sectional view of a slightly modifiedform of the invention.

The invention comprises a metallic sleeve or shell 'Z having theenlarged flat faced portion 8 and provided at ,one end with theperipherally threaded portion 9. The outer or upper end of the sparkplug is recessed as at 10, and internally threaded. 'I'helower end isslightly enlarged to provide the restricted centrally positioned opening11 and afford a shoulder 12. Resting against the shoulder 12 is theinsulating core 13 which is formed cup-shaped so` as to provide theelectrode receiving space or socket 14 which is internally threaded.

Threaded into this socket `14, is a. coiled electrode 16, the upper end17 of which is angularly turned and projected through the closing cap 18of insulating material. A nut 19 is threaded into the recess so as topress the cap 18 against l the upper or open end of the core 13 andforces the core 13 tightly against the shoulder or seat 12. This nut 19is provided with a central opening 20 into which the' curved side of thesemispherical cap 18 'may project. The angularly turned portion 17 ofthe electrode terminates inv a head 21 positioned within the insulatingabutment block22. The head 21 is connected to the (Cl. 12S- 169)terminal screw or stem 23 on which is threaded the nut 24. The lower endof the coiled electrode is angularly turned to provide the portion 25which cooperates with the sparking ,point 26 extending inwardly'from thelower end of the w shell 7.

1t is obvious that a maximum length of electrode is provided by the coilarrangement and, from the description given, the economy of manufactureand simplicity of assembly is believed evident.

1n the form shown in Fig. 4, We have provided a metal shell 27 havingthe hat faced portion 23 and the threaded portion 29. This sleeve orshell 27 has a bore 30 extended therethrough and .m

enlarged-at its lower end to provide the enlarged bore or recess 31 andaffording an abutment shoulder 32. A peripheral flange 33 on the insu'lating core 15 engages against the shoulder 32 and a neck 34 projectsoutwardly from the ange 33. This core 15 is provided with the internallythreaded socket 35 inwhich is threaded the coiled electrode 36, one end37 of which is angularly turned and threaded and projected through theinsulating washer 38. on the portion 37 as is also a binding nut 40. Thevlower end of the coil is angularly turned as at 41 and projectedoutwardly from the core to cooperate with the sparking point 42projecting inwardly from the shell 27. The locking nut 39 prevents thecore 15 from falling out of the shell and the engagement of the iiange33 with the shoulder 32 resists outward movement of the core when anexplosion takes place inthe engine with which used.

A lock nut 39 is threaded 80 A cup shape cover 43 is pressed into therecess w 44 of the shell 27 to assist in retaining the washer 38 inposition. The`nut 39 is preferably made from insulating material andwhen not made from insulating material is spaced from thecap 43 by asuitable washer.

In this form of construction the eiciency obtained in the form shown inFig. 1 is present and the economy of manufacture and simplicity ofassembly is also maintained.

The coiling of the electrode results in increased eillciency in that thespark is intensied. This permits ample sparking of theplug when a weakbattery is used, sorthat easy starting of the engine .with which used ispossible at all times.

While we have illustrated and described the preferred form ofconstruction of our invention, we do not wish to limit ourselves. to theprecise details of structure.k shown, but desire toavail ourselves ofsuch variations and modifications as 110 EID may come within the scopeof the appended claims. l l

Having thus described our invention which we claim as new and desire tosecure by Letters Patent is:

1. A spark plug of the class described comprising: a metallic shellhaving a bore formed therethrough, said shell having intermediate theends of said bore an engagement shoulder forming portion; an insulatingcore in engagement with said shoulder; means for retaining said core inengagement with said shoulder; an electrode projectedthrough said core,the portion of said electrode within said core being coiled, said corebeing threaded for the reception of the coil portion of said electrode.2. In a spark plug of the class described, a. metallic shell having abore formed therethrough; an insulating core mounted in said bore; meansfor retaining said core in said bore; and an electrode projected throughsaid core, the portion of said electrode within said core being coiled,said core being threaded for the reception of the coiled portion of saidelectrode.

GUSTAVE A. SHELL. BERNARD ZE'I'IERLUND.

